linux-kernel - Re: [PATCH v2] i2c: designwear: Fix clk warning on suspend/resume

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Date:   Thu, 2 Mar 2017 15:39:49 -0800
From:   John Stultz <john.stultz@...aro.org>
To:     Jarkko Nikula <jarkko.nikula@...ux.intel.com>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org
Subject: Re: [PATCH v2] i2c: designwear: Fix clk warning on suspend/resume

On Tue, Feb 14, 2017 at 7:30 AM, Jarkko Nikula
<jarkko.nikula@...ux.intel.com> wrote:
> On 14.02.2017 06:05, John Stultz wrote:
>>
>> On my HiKey board, I'm seeing clk warnings on suspend/resume,
>> which seem to be caused by runtime pm suspending the device,
>> then the same suspend hook being called again on suspend time.
>>
>> This patch fixes this by setting the SYSTEM_SLEEP_PM_OPS to
>> using pm_runtime_force_suspend and  pm_runtime_force_resume.
>>
>> Cc: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
>> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
>> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
>> Cc: Wolfram Sang <wsa@...-dreams.de>
>> Cc: linux-i2c@...r.kernel.org
>> Suggested-by: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
>> Signed-off-by: John Stultz <john.stultz@...aro.org>
>> ---
>> v2: Switch to suggested fix by Jarkko.
>>
>>  drivers/i2c/busses/i2c-designware-platdrv.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
>> b/drivers/i2c/busses/i2c-designware-platdrv.c
>> index 6ce4313..09f27ec 100644
>> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
>> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
>> @@ -362,7 +362,7 @@ static int dw_i2c_plat_resume(struct device *dev)
>>  static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
>>         .prepare = dw_i2c_plat_prepare,
>>         .complete = dw_i2c_plat_complete,
>> -       SET_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
>> +       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
>> pm_runtime_force_resume)
>>         SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
>>  };
>
>
> We need to hold this a bit. I've been debugging this on our platforms but
> haven't figured out yet how to fix a regression it is causing with
> drivers/acpi/acpi_lpss.c :-(
>
> With this change in i2c-designware-platdrv.c the suspend path in acpi_lpss.c
> changes. First it saves its the register context in
> acpi_lpss_runtime_suspend() and powers down. Then the device which is now
> off will save again the register context (now reads full of 0xff...) in
> acpi_lpss_suspend_late() and restores wrong context (0xff...) when resuming.

Hey,
  Just wanted to follow up to see if any progress was made on this
issue? Anything you need from me?

thanks
-john